1. Field of the Invention
This invention relates to a process of preparing ethylene-ethyl acrylate-acrylic acid terpolymer having a melt index of from about 50 to about 2000 decigrams per minute, from ethylene-ethyl acrylate copolymer having a melt index of from 0.1 to about 300 decigrams per minute by hydrolyzing the ethylene-ethyl acrylate copolymer in an inert atmosphere, at a temperature of from about 150.degree. C. to about 450.degree. C. and a pressure of from about 3 to about 300 kg/cm.sup.2.
2. Description of the Prior Art
Ethylene-ethyl acrylate-acrylic acid terpolymers find use in a variety of applications such as in the extrusion coating or paper, emulsion adhesives and aqueous paints, generally in the form of an aqueous solution of ammonium salt, for example. Ethylene-ethyl acrylate-acrylic acid terpolymers have been prepared by the alkaline or acidic hydrolysis of ethylene alkyl acrylate copolymers as described in U.S. Pat. No. 3,249,570, for example. Acidic hydrolysis conditions utilize sulfuric, phosphoric or hydrochloric acid, while basic hydrolysis conditions utilize a base, such as sodium or potassium hydroxide. Also, ammonium type hydrolyzing agents can be used. These acidic or basic hydrolyzing agents corrode the autoclave excessively at temperatures suitable for chain scission. Additionally, the use of alkali metal hydroxides requires an additional step of freeing the product from the inorganic salts. Also, use of ammonium hydrolyzing agents results in amide formation.